Biochemical and genetic experiments are proposed to study the parameters of DNA polymerase which influence the incorporation and removal of errors during DNA synthesis. The system being investigated is the bacteriophage T4 including the wild-type phage and several temperature-sensitive gene 43 mutants having both increased and decreased spontaneous mutation frequencies. Several antitumor antibiotics including adriamycin and daunorubicin have been shown to inhibit and activate differentially purified DNA polymerases coded for by the mutant and wild-type phage. We are studying the molecular basis for these differential effects. BIBLIOGRAPHIC REFERENCES: J.K. Harman, H. Berger, and M.F. Goodman. Tryptophan Operon Read-Through. J. Biol. Chem. 250, 4624 (1975). M.F. Goodman, Y.S. Chang, and N.R. Bachur Response of mutant and wild-type DNA polymerases to Antracycline derivatives. Fed. Proc. 34, 493 (1975).